I have been on a hunt for the past several years to find a cheap and simple, yet moderately high resolution 3D printer. I had 3 different 3D printers partially constructed when I heard about the amazing technology of DLP Stereo lithography (SLA) printers. I have finally found enough parts at the right price to construct a fully functional printer capable of amazing quality with spending less than $100. Top down DLP printers in their simplest form have only one axis of motion, a video projector, and minimal electronics. They do not require a heated or perfectly level bed, there is never a clogged or wrong temperature in the extruder as it does not use an extruder. And the resin used has a comparable price to FDM printers.
I Started this project to show that you don't need a lot of money or special equipment to start experimenting with 3D Printing. While this printer was not meant to give the same quality as an expensive printer such as the form 1, the results I got exceeded my expectations. There are still a few bugs to work out but, it definitely is usable. If you would like to see a video of it printing, the video is in Step 12.
The chimera (ky-meer-a) is a mythological creature that is made up of 3 different animals, this printer is made using the recycled/modified parts of 3 different categories (projector, toys, and old computer stuff), hence the name.
I am always looking for constructive criticism, let me know of any ways I can improve on the project, or the instructable!
Before continuing I would like to apologize for the not-up-to-current-standards pictures and video quality, I am working with almost or over a decade old equipment in bad lighting. I will try to update the photos once I get a better quality camera and/or find a better location for pictures.
Update 7/14/15 This project won one of the enthusiast grand prizes in the 2015 3D printing contest. Thank you everyone for their votes, and thank you instructables for continuing to be the best online DIY community! I am glad I could contribute to this site and hope my next project will spark as much interest as this one did.
Let’s start out with the basics, in 1986 Charles W. Hull created stereo-lithography as a form of fabrication that uses ultraviolet light to cure a polymer resin to create solid objects. Since then, projection technology has opened up a highly accurate, fairly cheap, and easily accessible form of ultraviolet emission. A DLP printer is different from the "normal" FDM (fused deposition molding) 3d printers that have been dominating the community, an FDM machine uses an extrusion system similar to an advanced hot glue gun that is attached to an apparatus that can move the extruder in an X, Y, and Z direction. The extruder must follow a path made by a computer to print objects. A DLP printer uses the stationary projector to display the entire X and Y portions at once onto a resin that turn from a solid into a liquid from the light emitted by the projector in the shape of the projected image, and uses one axis for the Z motion.
Top Down vs. bottom up
Even though bottom up printers are capable of printing larger and higher quality objects with less resin, I decided to build a Top down printer for its simplicity and ease of construction.
Edison once said "invention requires imagination and a pile of junk." I had a few ideas, so it was time to head to the pile of junk (really, I have one). Out of that pile came old printer carriages, steel smooth rod, old disk drives, stepper motors and other misc electronics. The one part that I had to buy was the DLP projector.
(optional for frame) scrap wood->free or 2x4ft MDF board ->$10 home depot
While the actual 3d printer can be built for less than $60 you will still need resin to print anything.
MakerJuice red G+ resin -> 500ml for $35 or 1L for $60
I only spent $39.99 for the projector, and got the resin for "free" using gift cards acquired from bing rewards. And I already had all of the other parts. So I built this for a total cost of only $39.99, which is very good especially considering the quality of the parts that it prints.
There are many projectors out in to market today, and as this is the most important part of the 3d printer, it is important to choose a good one. There are a few projectors i see referenced as being used for 3d printers, namely the the dell 2300 and 2400, and the infocus 2104. But in theory any DLP projector can work as long as you keep a few thing in mind when choosing a projector.
You need a projector that uses DLP(Digital Light Processing) technology for projection. DLP technology uses an array of micro mirrors to turn pixels on and off. The mirrors reflect the light directly from the bulb to the emitter lens without passing through much.
What you don't want is an LCD(Liquid Crystal Display) type of projector. LCD projector direct the light through an LCD panel that uses transistors to turn pixels on and off, if the pixel in on, then the light has to pass through several layers of plastic, glass, and polarizing filters before the image gets projected. Much of the UV light that is needed to cure the resin gets absorbed by the LCD panel and there will not be enough left over to cure the resin. once again, LCD projectors can NOT be used for resin based 3d printing (that i know of)
Resolution (or res for short) is the number of pixels that the image is projected at. The native resolution of the projector is very important as it will determine the quality of the printed object. Common resolutions for projectors are 800x600, 1024x768, 1280x800, 1280x1024, and 1600x1200. Obviously the higher the resolution, the better the quality of the printed objects will be, but high-res projectors are not cheap. i would recommend not going any lower than 1024x768, which is the most common, but it is possible to go with lower res projectors, just don't expect great results.
NOTE: there is a difference between supported and native resolutions. supported resolutions is the max resolution of the video feed that is given to the projector. Native resolution is what the actual projected image will be displayed at. be careful of advertising "scam" that will make it sound like an amazing 1080p (1920x1080) quality projector, but the quality is actually terrible and usually around 400x320. This is something that usually happens with Chinese no-name projectors, but it is still important to be aware of the difference.
This is how bright your projector will display the image at. The higher the lumen rating the projector has, the faster it will be able to cure then resin. I don't know what the minimum rating is, but the xd221u projector is rated for 2300 lumens and it takes longer than i would like for each layer at 10 seconds exposure time.
While the XD221u will not cure the resin without modifications, the focus distance is too far and the curing time is too long at 15 seconds exposure per layer. The focus had to be modified for close distances and the UV filter had to be removed allow more UV light through. Making it cure the resin faster is easy, just remove the filter (glass square) on the front of the bulb. Making the projector focus at ≈7" was a bit more difficult. The service manual has been attached for assistance in dis-assembly if you are using an xd221u projector, but the modification should be similar for most projectors.
WARNING: I am not responsible for any damage, injury, blindness, death, etc. that may be inflicted upon you during these instructions. Your actions are your own and you should know what is and isn't safe to do. Use common sense and you will be fine.
Now for the fun part. The steps correspond roughly to in order of the pictures
Modifying the focus
1-3. Remove the bulb cover and bulb from the projector. There are two screws and two clips holing the bulb in.
4. Remove the 8 screws from the bottom of the projector
5-6. Remove the three screws holing the back plate on, and use a flat head screwdriver to remove the back plate.
7-9. Lift the top of the projector off being careful not to rip the ribbon cable connected to the top buttons. Lift the clip holding the cable to the motherboard and slide the cable free.
10-12. Remove the zoom adjustment piece by prying out the 2 clips holding it in. Then remove the zoom frame by screwing the two screws holding it in place.
(WARNING: for the next several steps do not touch any of the lenses or you will not be able to get a clear picture after you are done.)
13-14. Remove the four screws holding the focus lens assembly in place, there is very little room for a normal screwdriver here, I had to use pliers and a Philips piece from a multi-head screwdriver. To remove and replace these.
15. Turn the assembly upside down and rotate the focus lens outward until its stops, inspect the circumference of the body of the focus assembly and you should see a very small screw that is screwed into the focus lens housing and is colliding with the outer assembly case. This is the screw that prevents the lens from unscrewing too far.
Remove this screw. You will now be able to turn the lens farther to focus at a closer distance. (WARNING: removing this screw allows the focus lens to be unscrewed all the way and fall out of the projector if turned too far, be aware of this as you focus the projector)
16. Re-assemble the projector but don't put the bulb in yet. Reverse the steps used to disassemble. The lens can now turn far enough to focus at close distances, which is needed for high resolution prints.
16-18. For the xd221u, there is a tab on the focus lens that will prevent the lens from turning to far, this is both good news and bad news. the good news is that I can use this to prevent the lens from falling out if it gets turned too far, the bad news is that the lens still can't turn far enough to focus at the distance I was looking for. To fix this use a file and slowly file down the tab until there is 1-2mm of distance from the tab to the projectors case.
I found that the lens will fall out when turned to around 300° (looking head on with 0° at the right) so I super-glued a scrap piece of scrap plastic to the case about 5mm from the point the lens will fall out to stop the lens from turning too far. This gives me a focus distance of approximately 6.75 inches from the front of the projector and a projection area of 4in wide by 3in tall.
Modifying the bulb - Then I needed to remove the UV filter to make the layers cure quicker.
19. If you are at the right angle you can see the square piece of glass at the front of the bulb that is the UV filter.
20. Remove the screw holding the metal plate on.
21-22. Use a small flat head to pry the metal clips out and up.
23. Remove the UV filter by lifting the glass out or by tilting the bulb until it falls out into your hand.
24. keep the UV filter in a safe and protected place, if you ever want to use the projector to watch movies or play games on, you will need to put the filter back in.
Put the bulb back in to projector, and turn it on. If everything works, well done! if not, open it up make sure that the ribbon cable for the buttons is attached correctly, no other cables were disconnected, and that the circuit board didn't suffer any damage. Connect a video source. Turn the focus as far as it will go without falling out, use a piece of paper or the wall to measure a rough estimate of the focal distance, this will be fine-tuned after it is attached to the printer.
The Z axis is the second most important part of the printer. It must be able to move smoothly without any wobble or twisting. I was considering constructing one, but that would require a significant amount of measuring, cutting, drilling, having to work with linear bearings, attachment plates, bells and pulleys, or lead screws, backlash, and all the other stuff associated with linear motion, or i could settle for a smaller but easily acquired, free, pre-built, and extremely fine precision assembly that has everything needed in one package.
As many people have found, a laser deck assembly from a computer disc drive is perfect for this purpose. the one i used is one that i have had around for a while, waiting for a good use for it. I do not know what model drive it came out of, but any assembly will work as long as it uses a stepper motor (4 wires) and not a DC motor (2 wires). As a rule of thumb the newer the disc drive, the more likely that it will be the correct type of motor, I've taken at least 50 apart over the years and i would estimate 90% of the DVD burners i have taken apart contained the correct motor while only 50% off DVD players and only 10% of CD players had the correct motor.
These pictures are for reference of how to take a drive apart and what you want from the drive. while i did not use this particular assembly it does fit the requirements and could be used. I would like to thank groover and his excellent pocket laser engraver instructable for bringing disc drive laser decks to my attention as viable candidates for linear motion.
Dissemble the Disc drive
Once you have taken the deck out of the disc drive, solder four 6inch wires and a four pin female header to the stepper motor. This will be used to connect to the shield that will be made later.
The only requirement for the build platform is that it is made from a material that your print will stick to without peeling itself up, yet will not force you to pry the object off and potentially damage the print in the process. The material I see used most often is aluminum. I had a piece of 1mm thick aluminum sheet that was part of the back light housing for an LCD monitor. After measuring the resin vat dimensions I scratched the design into the sheet and cut it with tin snips. Then bent the cut out at a 90° angle to form the build platform and the suspension beam. I had to bend the beam in the middle move the platform farther away from the z axis to fit properly in the resin tank. When cutting the sheet metal I made the platform 4mm smaller than the resin tank which gave 2mm clearance on each side to allow the resin to move freely from below the platform to above the platform without any pressure building up.
The resin tank for top down printers are fairly simple. Almost any container can be used as long as you follow a few guidelines.
The container must be
I looked at my options and decided on the top from an acrylic container that i had lying around, it is roughly 50x50x35mmind is sufficient for the prototyping stage. I recently found a glass container at goodwill for $.50 that is 3" diameter and 3 inches deep which should work perfectly for my needs.
This machine was built with two frames, one to hold the z axis, platform and resin tank, which I am calling the Zframe. The other frame simply holds the projector above the zframe, and allows the zframe to move up and down to allow the projector to focus on different resin tanks.
Z axis, platform, and resin tank
I like to design as I go along, so I turned to the most versatile prototyping material in existence, LEGOs. Yes these are technically a toy, but i have not found any other materials that allow you to quickly construct, make small changes, or tear down a bad idea as easily as LEGOs do. The requirements for the zframe were...
The z axis mounting problem is something that I had solved a while ago for a different purpose, but it worked well for the Chimera. As pointed out earlier, LEGO technic bushings fit very well into the rubber/plastic mounting holes that already exist in the laser deck, so all that was needed to mount the laser deck was four Lego axles protruding from a wall in the right locations.
The vertical spacing is easily adjusted by how many layers of full bricks and flat bricks are used. But most laser decks will not fit the standard spacing of technic beam holes. This issue was solves by mounting LEGO axles within the wall that allow a Tpin to slide for any spacing.
something to be aware of is that when any resin touches the LEGOs it has a similar effect that gallium has on aluminum(video), essentially it will make the LEGOs disintegrate. So if you don't mind if some LEGOs get destroyed then go ahead and use LEGOs, it didn't bother me as these were actually megablocks ;). otherwise you can make the frame out of wood, which I am planning to do once I decide on the final size vat I am going to use.
For the main from the only requirements were that it held the projector up and had a space for the zframe below the projection area. While LEGOs could be used, I've found that interlocking bricks are not good for large and stable structures. So I turned to the other "toy" that can make large, lightweight, and sturdy structures, yet has a similar flexibility for alterations to the design as Legos do, and that is K'nex.
Several years ago i was heavily involved with the k'nex community here on instructables, making everything from the Foldable knex gun to the 5 foot cannon and in doing so i discovered the amazing strength and versatility of K'nex, and have amassed over 100lbs of it. it is an excellent tool for learning the physics behind large structures, and how to make large structures that can withstand a significant amount of forces acting upon them.
K'nex made constructing the frame easy, its simply a base, two towers and an adjustable platform to accommodate for different size resin tanks until I find a suitably permanent one.
As promised I have designed a frame that can be completely out of wood for anyone who does not have Legos or K'nex. I made this one out of a 11.5"x28"x.5" particle board shelf that I pulled out of the trash with a circular saw and a drill press. Home depot has a 24"x48"x.5" MDF for $10 that is more than enough wood and will work better than the particleboard I used. The SolidWorks CAD files are at the end of the step, I will make blueprint files from the SolidWorks files soon. I will also make printable PDF documents that can be used as stencils if for those who like to use those.
One of the best features of a top down system is the simplicity of the electronics. Instead of the expensive Arduino MEGA and RAMPs shield that many DIY 3D printers use to control the many features, the cheap Arduino UNO can be used because there is only one axis to control and maybe a shutter (optional). I etched a shield for the Arduino, which I designed in Cadsoft EAGLE. But if that is not something you are able to do, fear not! the schematic is simple and can easily be made on a breadboard. If you want to put a little more work into it, you can program an ATMega328p chip with the firmware and etch a all-in-one board whose design is included in the files attached.
The Shield has 1/8th microstepping enabled for high resolution movement.
I tried several different firmwares for the Arduino UNO before deciding to use GRBL 0.9i. In my experience, GRBL is the best option for print quality, compatibility, ease of use, and customization. To get your arduino setup for the printer you will need to upload the GRBL firmware, and configure GRBL to your machines specs. Download the attached zip file and extract it to the desktop. Connector your arduino to the computer.
Uploading the firmware
GRBL firmware is in .hex format, and the arduino software does not allow you to upload .hex file to the arduino, so we will be using a different program called xloader.
You are now able to use the Arduino for controlling your printer.
Out of the many open source software options that I looked at, only Creation Workshop by envision labs seemed to provide the compatibility and customization options that I required. I have included the zip file that contained the software and settings I used pre-setup, but it may require some tweaking for your own machine. Start by extracting the zip file to the desktop or other location. Open up CreationWorkshop.exe and follow the instructions.
Configure the machine
Configure the Slicing Profile
Profile selection - Click the plus button to create a new profile and name it chimera (or whatever you want)
3. Lift and sequence -
4. Auto Calc - this will calculate the estimated time that it will take for the printer to complete the lift sequence, this is important as it is the time for which the software waits before projecting the next layer.
5. Build Direction - VERY IMPORTANT - make sure that you have top_down selected as the printer type. your printer will not work if the wrong type is selected.
6. Apply changes - make sure that you click this to save any changes you have made before moving on.
I would highly recommend using a second computer to run your software on, while you can use your computer at the same time you are printing, there are many things that could go wrong if you are doing other activities such as browsing the Internet (instructables addiction? guilty.) or playing games.
1. Pop-ups - these can cause MAJOR print failures. remember that the projector is connected as second computer monitor, so any popup can appear on the second monitor resulting the the projector displaying a totally white screen and hardening the entire top layer of the resin, which will ruin your print without hope of recovery, be very difficult to remove, and is a waste of material.
2. Slow/freezing issues - if the computer runs slow or hangs up due to an excessive load on the processor or graphics card, creation workshop can freeze mid-command or even skip commands, with will result in a failed print.
In order to avoid these problems its recommended that you do not touch the computer while you are printing an object.
In order to get the best quality prints you will have to calibrate the machine. This involves making sure that the projector is at the optimal focal distance from the build platform, and that the X and Y dimensions or correct. Make sure the machine is plugged in and turned on before starting.
Focusing the projector
Calibrating the prints
Congratulations! It is now time to actually see what this printer can do, but before making anything detailed, the X and Y dimensions need to be calibrated.
Load the calibration cube
Once the print has dried you usually need to perform some sort of post-cuing process to fully harden the resin. There are several options for this.
Calibrating the X and Y axis.
Now that you have your calibration cube printed it likely that it’s not exactly square or the wrong size, this is normal and easily fixed.
Your done! Go enjoy your new printer! If you made one I would really like to see it and the results. If you have any questions, concerns, or comments, let me know! I will respond as soon as I can. If you liked my instructable please vote for it in the 3D printing contest, while this machine can do very fine details and is an amazing printer, it still cannot do the large scale or structure parts that a FDM Printer can do, and I have So many ideas that require the abilities of a FDM 3D printer. Thanks for looking and I hope you enjoyed this instructable!
I Started this project to show that you don't need a lot of money or special equipment to get started experimenting with 3D Printing. While this printer was not meant to give the same quality as an expensive printer such as the form 1, however the results I got exceeded my expectations. There are still a few bugs to work out especially with large flat objects (they are curling way too much), but it definitely shows promise. These are several of the prints that i have made, I will update with more pictures as I print more objects. The black line in the microscope images is a human hair for size comparison. The T-Rex's nose collapse was my fault, I accidentally deleted the support for it before I printed it.
This is list of upgrades that I will be making in the future along with dates and times set as the goal for completion. It is likely that some of the goals will be completed much earlier than the set times, or in a different order. If I complete enough modifications, I might make a Chimera V2.0 instructable that details all of the updates.